ARC HYDRO GROUNDWATER TUTORIALSahgw.aquaveo.com/Transient.pdfmultidimensional groundwater data. It includes several components to represent different types of datasets, including representations

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ARC HYDRO GROUNDWATER TUTORIALS

Working with Transient MODFLOW Models

Arc Hydro Groundwater (AHGW) is a geodatabase design for representing groundwater

datasets within ArcGIS. The data model helps to archive, display, and analyze

multidimensional groundwater data. It includes several components to represent different

types of datasets, including representations of aquifers and wells/boreholes, 3D

hydrogeologic models, temporal information, and data from simulation models.

The Arc Hydro Groundwater Tools help to import, edit, and manage groundwater data

stored in an AHGW geodatabase. The MODFLOW Analyst is a tool set within the

AHGW Tools that is used to manage groundwater simulation models based on the

MODFLOW code developed by the United States Geological Survey.

Currently, MODFLOW Analyst tools support only models in MODFLOW 2000 and 2005

format. If using a different version, the USGS utilities can be used to convert the model to

MODFLOW 2000 or 2005 formats.1 For details on the MODFLOW Data Model, please

review the article on the XMS Wiki.2

1 Introduction

This tutorial discusses and demonstrates working with a transient MODFLOW model of

the Cache Valley in northern Utah, corresponding to the location shown in Figure 1. There

are two versions of the Cache Valley model: steady state and transient. This tutorial works

with the transient version of the model. The model has 6 layers, 82 rows, and 39 columns

and 9 stress periods. The “Working with MODFLOW Models – Steady State” tutorial

covers using a steady state model using the same location information.

1 See https://www.usgs.gov/mission-areas/water-resources/science/modflow-and-related-

programs for more details.

2 See https://www.xmswiki.com/wiki/AHGW:MODFLOW_Data_Model for more details.

https://www.usgs.gov/mission-areas/water-resources/science/modflow-and-related-programs

https://www.usgs.gov/mission-areas/water-resources/science/modflow-and-related-programs

https://www.xmswiki.com/wiki/AHGW:MODFLOW_Data_Model

Arc Hydro Groundwater Tutorials Working with Transient MODFLOW Models


Figure 1 Location of the Cache Valley model

1.1 Outline

The objective of this tutorial is to introduce the basic components and features of

MODFLOW Analyst through completing the following tasks:

Review the sections in the MODFLOW Data Model dealing with transient data.

Generate map layers illustrating transient MODFLOW data.

Import and display transient MODFLOW solution files.

Create plots of MODFLOW inputs/outputs.

1.2 Required Modules/Interfaces

The following components must be enabled in order to complete this tutorial:

Arc View license (or ArcEditor\ArcInfo)

Arc Hydro Groundwater Tools

AHGW Tutorial Files

The AHGW Tools require a compatible ArcGIS service pack be installed. Check the

AHGW Tools documentation to find the appropriate service pack for the version of the

tools being used. The tutorial files should be downloaded to a local computer.

1.3 Getting Started

Before opening the map, make sure that the AHGW Tools and AHGW Toolbar are

installed and available.



1. Launch ArcMap.

2. Open the ArcToolbox window by clicking on ArcToolbox.

3. If the “ Arc Hydro Groundwater Toolbox” is not in the list of toolboxes, right-

click in a blank space in the ArcToolbox window and select Add Toolbox… to

bring up the Add Toolbox dialog.

4. In the “System Toolboxes” folder, select “Arc Hydro Groundwater Toolbox.tbx”

and click Open to exit the Add Toolbox dialog.

5. In the ArcToolbox window, expand “ Arc Hydro Groundwater Toolbox” and

“ MODFLOW Analyst".

The MODFLOW Analyst Toolbar contains additional user interface components not

available in the toolbox. If the toolbar is not visible, do the following:

6. Right-click on any visible toolbar and select MODFLOW Analyst Toolbar.

When using geoprocessing tools, the tools can be set to overwrite outputs by default. To

set this option:

7. Select Geoprocessing | Geoprocessing Options... to bring up the Geoprocessing

Options dialog.

8. In the General section, turn on Overwrite the outputs of geoprocessing

operations.

9. Click OK to close the Geoprocessing Options dialog.

2 Opening the Map

Begin by importing a map containing some background data, MODFLOW features, and

MODFLOW tables for the Cache Valley transient model.

1. Click File | Open… to bring up the Open dialog.

2. Browse to the Tutorials\modflow analyst\transient folder for this tutorial.

3. Select “cache_tr.mxd” and click Open to exit the Open dialog.

A map of Cache Valley in Utah and Idaho will appear (Figure 2). The file contains a map

layer representing the states in the region, MODFLOW features (cells, nodes, boundary

polygon), and MODFLOW tables. To save time, the MODFLOW features and tables were

already created by importing a MODFLOW model.



Figure 2 Map showing the Cache Valley

3 Temporal Referencing of Model Stress Periods

Temporally reference the model in real world date/time by running the Add SP Start and

End tool. It adds the StartDate and EndDate fields to the “StressPeriods” table and

populates the beginning and end date of each stress period. This enables querying the data

in the MODFLOW tables and to generate maps based on real dates/times and not only by

stress period ID.

3.1 Setting the Temporal Origin

Before running the tool, the temporal origin (RefTime) of the model should be set. This is

the starting date/time of the first stress period:

1. In the Table of Contents, right-click on “DISVars” and select Open to bring up

the Table dialog.

2. Notice that "seconds" is in the ITMUNI column.

3. Notice that the RefTime column has a null value.

The value in the ITMUNI column needs to be set in order to calculate the starting and

ending dates of the stress periods. This is done by using the Field Calculator on the value

in the RefTime column.

4. Right-click on the RefTime column header and select Field Calculator… to bring

up the Field Calculator dialog.

5. If advised the calculation will be outside an editing session, click Yes.

6. Enter “#1/1/2000#” in the RefTime field.



7. Leave all other settings at the defaults.

8. Click OK to close the Field Calculator dialog.

The value “1/1/2000” should appear in the RefTime column.

9. Click the X in the top right corner to close the Table dialog.

3.2 Calculating the Stress period Dates

Next, calculate the beginning and end dates for each stress period based on the data in the

StressPeriods table and the RefTime value just entered:

1. In the ArcToolbox window, expand “ Arc Hydro Groundwater Toolbox”, then

expand the “ MODFLOW Analyst" and “ Stress Period" toolsets.

2. Double-click on “ Add SP Start and End” to bring up the Add SP Start and

End dialog.

3. Select “DISVars” from the Input DISVars Table drop-down.

4. Select “StressPeriods” from the Input StressPeriods Table drop-down.

5. Click OK to close the Add SP Start and End dialog and open the Add SP Start

and End wrapper dialog.

6. When the tool finishes, click Close to exit the Add SP Start and End wrapper

dialog.

7. Right-click on “StressPeriods” in the Table of Contents and select Open to bring

up the Table dialog.

8. Scroll to the far right in the table and notice that two columns were added and

populated: StartDate and EndDate.

The transient model contains 9 stress periods, indexed in the SPID column.

9. Notice PERLEN column. It contains the length of stress periods, set to 31557600

seconds (one year).

10. When done reviewing the data in the table, click the X in the top right corner to

close the Table dialog.

4 Building Map Layers of Transient Data

Next, generate map layers of transient data and filter the layers based on the SPID and real

date/time values.

The relationships between MODFLOW features (cells and nodes) and data stored in the

MODFLOW tables are used to create map layers illustrating the MODFLOW data. The



Create MODFLOW Features tool is used to create the map layers. Start by creating a map

layer of the well package (WEL) data.

1. In the ArcToolbox window, expand “ Views" under the “ MODFLOW

Analyst" toolset.

2. Double-click on “ Create MODFLOW Features” to bring up the Create

MODFLOW Features dialog.

This tool makes map layers out of Cell2D, Node2D, and Node3D features. The Input

Cell/Node Features field is used to specify which type of feature is to be used in the query.

3. Select “Node2D” from the Input Cell/Node Features drop-down.

4. Select “WEL” from the Input MODFLOW Table drop-down.

The Additional Filtering Expression field can be used to specify any additional items to the

SQL query that are not part of the standard query. In this case, leave it empty.

5. Turn on SPID, Q, and QFact from the list in the MODFLOW Table Fields of

Interest field.

The MODFLOW Table Fields of Interest controls are used to select which of the fields

from the MODFLOW table will be added to the new feature layer.

6. Click to the right of the Output MODFLOW Feature Class field to bring up

the Output MODFLOW Feature Class dialog.


8. Double-click on “Cache_tr_MODFLOW.mdb”.

9. Double-click on “Layers”.

10. Enter “Wells” and click Save to exit the Output MODFLOW Feature Class

dialog.

The Output MODFLOW Feature Class field is used to specify the name and location of

the new feature class that will be created by the tool.

The Grid Layer (K) filter allows selecting to map only a specific layer. Leave the Grid

Layer (K) value empty to map all layers.

11. Turn on Only Active Cells.

This ensures only active cells will be used in the query.

12. Expand the MODFLOW Tables section.

13. Make sure “Basic” is selected from the Input Basic Table drop-down.

14. Make sure “BasicArrayMult” is selected from the Input Basic Array Multiplier

Table drop-down.

15. Make sure “CellIndex” is selected from the Input CellIndex Table drop-down.



16. Make sure “DISVars” is selected from the Input DISVars Table drop-down.

17. Click OK to close the Create MODFLOW Features dialog and open the Create

MODFLOW Features wrapper dialog.

18. When the tool finishes, click Close to exit the Create MODFLOW Features

wrapper dialog.

A new “Wells” layer should appear in the Table of Contents and the wells should appear

at various places around the Cache Valley (Figure 3). Similarly, other packages can be

mapped using the Create MODFLOW Features tool. Feel free to repeat these steps to

build map layers for the RIV, RCH, and EVT packages, if desired.

Figure 3 Detail of project showing wells scattered across the Cache Valley

5 Using the MODFLOW Stress Period and K Filters

The Create MODFLOW Features tool created a feature class containing overlapping cells,

as a cell is created for each layer (K) and for each stress period (SPID). One of the fields

in the feature class is the “WEL_SPID” which was carried over from the WEL table when

the new features were created. This field indicates the stress period of the data.

A map of the well data for a certain stress period can be created by applying a definition

query (SPID=1) to the current map layer using the Layer Properties dialog. The

MODFLOW Analyst toolbar contains a convenient shortcut for creating a definition query

based on the SPID.

To use the filter:

1. In the Table of Contents, select the “Wells” layer.

2. Change both K and SPID in the MODFLOW Analyst Toolbar to “1”.



The default values for each are “0”, which displays all layers and stress periods at once.

The SPID can be combined with the K filter to filter layers by SPID and by the grid layer

(K) value.

3. Repeat step 2, cycling through all of the layers and SPIDs as desired.

The SPID filter works for any map layer containing an SPID field. To apply it to multiple

map layers at once, simply select multiple map layers in the Table of Contents prior to

changing the value in the SPID filter.

6 Importing and Displaying Output Data

The output from a MODFLOW simulation includes head, drawdown, and flow data. The

OutputTime table is used to store the time steps of the simulated outputs (head, drawdown,

and flow). The table includes the following fields:

TimeID – The unique identifier for the stress period\time step combination, and

uniquely identifies each output time step.

SPNum – The stress period number from the MODFLOW output file.

TSNum – The time step number from the MODFLOW output file.

Each of the output time steps is described by a number of time values:

TotalTime – The time from the beginning of the model simulation (t=0).

PeriodTime – The time from the beginning of this stress period.

AbsoluteTime – The real date/time.

Viewing output from a MODFLOW simulation requires importing the output files into the

tables. The Create MODFLOW Features tool can then be used to display the output data.

6.1 Verifying the MODFLOW Name File Path

Before importing the files, make sure that the file locations are specified correctly. The

MDFGlobals table includes a NameFilePath field that includes the path to the

MODFLOW name file:

1. In the Table of Contents, right-click on “MDFGlobals” and select Open to bring


2. Notice that the path to the MODFLOW Name File is in the NameFilePath

column.

3. When done reviewing the path, click the X in the top right corner to close the

Table dialog.



6.2 Modifying the MODFLOW Name File Path

The path may need to be modified to match the folder location on the computer being used.

To modify the path:

1. On the Editor Toolbar, select Editor | Start Editing.

2. Right-click on “MDFGlobals” in the Table of Contents and select Open to bring


3. In the NameFilePath column, edit the path to match the location of the

“Cache_TR.mfn” file in the tutorial files’ Out_Mf2k_trans folder.

4. Select Editor | Save Edits to save the path change.

5. Select Editor | Stop Editing to end the editing session.

6. Click the X in the top right corner of the Table dialog to close it.

6.3 Importing MODFLOW Output Files

To import the MODFLOW output files, do the following:

1. In the ArcToolbox window, expand “ Import" under the “ MODFLOW

Analyst" toolset.

2. Double-click on “ Import MODFLOW Output” to bring up the Import

MODFLOW Output dialog.

3. Turn on Import Head File.

Head, drawdown, and flow results files can be imported individually or together. In this

tutorial, only the head file will be imported.

4. Click OK to close the Import MODFLOW Output dialog and bring up the Import

MODFLOW Output wrapper dialog.

5. When the tool finishes, click Close to exit the Import MODFLOW Output

wrapper dialog.

When the tool is finished, the display does not change because the tool simply imports the

output data into the appropriate tables. Feel free to view the data imported by opening the

“OutputHead” table. Note that a head value of “1” represents “no value”.

6.4 Generating a Head Map Layer

Next, generate a map layer of heads.

1. In the ArcToolbox window, expand “ Views" under the “ MODFLOW

Analyst" toolset.



2. Double-click on “ Create MODFLOW Features” to bring up the Create

MODFLOW Features dialog.

3. Select “Cell2D” from the Input Cell/Node Features drop-down.

4. Select “OutputHead” from the Input MODFLOW Table drop-down.

5. Turn on TimeID and Head in the MODFLOW Table Fields of Interest list.

6. Click to the right of the Output MODFLOW Feature Class field to bring up

the Output MODFLOW Feature Class dialog.


8. Double-click on “Cache_tr_MODFLOW.mdb”.

9. Double-click on “Layers”.

10. Enter “Heads” and click Save to exit the Output MODFLOW Feature Class

dialog.

11. Leave all other options at their defaults.

12. Click OK to close the Create MODFLOW Features dialog and bring up the

Create MODFLOW Features wrapper dialog.

13. When the tool finishes, click Close to exit the Create MODFLOW Features

wrapper dialog.

A set of head cells should appear (Figure 4, coloring may differ) and a new “Heads” layer

will appear in the Table of Contents.



Figure 4 Head cells now visible

6.5 Setting Up Layer Symbology

Next, set up the layer symbology. Since there are a lot of unique head values, carefully set

up the sampling.

1. In the Table of Contents, right-click on “Heads” and select Properties… to bring

up the Layer Properties dialog.

2. On the Symbology tab, in the Show section, select Quantities and then Graduated

colors.

3. In the Fields section, select “OutputHead.Head” from the Value drop-down.

4. Click OK if advised the maximum sample size has been reached.

5. In the Classification section, click Classify… to bring up the Classification

dialog.

6. In the Data Exclusion section, click Sampling… to bring up the Data Sampling

dialog.

7. On the Data Sampling tab, enter “100000” as the Maximum Sample Size.

8. Click OK to close the Data Sampling dialog.

9. In the Classification section, select “10” from the Classes drop-down.

10. Click OK to close the Classification dialog.



11. Click Apply, then click OK to close the Layer Properties dialog.

The cells in the “Heads” layer should now be using a color gradient (Figure 5).

Figure 5 Head cells with gradient coloring

7 Using the MODFLOW Time Filter

To view output data, use the Time drop-down on the MODFLOW Analyst Toolbar to

display data for a given layer and output time. It creates a definition query on selected

layers to simplify the process of visualizing output data.

1. In the Table of Contents, select the “Heads” layer.

2. Right-click on the Time drop-down and select TimeID.

3. Select a value from the Time drop-down.

Notice that the Time Information section to the right of the Time drop-down is updated

with relevant information from the “OutputTime” table, including the stress period, time

step, total time (time from the beginning of the simulation), period time (time from the

beginning of the stress period), and absolute time (date/time of the output time).

When using the Time filter, create a display of data for all layers. To create a more

meaningful view, set the K filter to restrict the data to a single layer.

4. Select a value of “1” for the K filter.

5. Select “5” from the Time drop-down.

The Time Information section of the MODFLOW Analyst Toolbar should update to

appear as in Figure 6. Making any changes to either the K or the Time filters will change

this information and the display.



Figure 6 MODFLOW Filter after selecting TimeID = 5 and K = 1

The head layer should be updated to show heads in layer 1 for TimeID 5 (Figure 8Error!

Reference source not found.).

The right-click menu gives options for the type of time data to populate in the filter. The

drop-down box should now be populated with a list of TimeID values. These values are

from the “OutputTime” table. Now select a different type of time data to display.

6. Right-click on the Time drop-down and select AbsoluteTime.

7. Select “1/1/2004” from the Time drop-down.

This changes the Time Information section: (Figure 7Error! Reference source not

found.).

Figure 7 MODFLOW Filter after selecting AbsoluteTime = 1/1/2004 and K = 1

Figure 8 Head layer updated based on filter selections

8 Plotting Transient MODFLOW Data

Another way to view transient data is to plot the change of a variable over time. Use the

Time Series Grapher to automate this process and create plots of different MODFLOW

inputs and outputs.



For this tutorial, plot the simulated heads at selected cells:

1. In the Table of Contents, select the “Heads” layer.

2. Select a value of “1” for the K filter.

3. Select null (the blank line) from the Time drop-down.

Because the plotter works similarly to the identify tool, it is better to use it on a layer that

doesn’t have overlapping features.

4. Click Time Series Grapher to bring up the Time Series Grapher Setup dialog.

5. In the Features section, select “Heads” from the Layer drop-down.

6. Select “CellIndex_IJK” from the Unique ID Field drop-down.

7. In the Time Series section, select “OutputHead” from the Table drop-down.

8. Select “IJK” from the Feature Identifier Field drop-down.

9. Select “TimeID” from the Date/Time Field drop-down.

10. Select “Head” from the Value Field drop-down.

11. Click OK to close the Time Series Grapher Setup dialog.

12. Click on any MODFLOW cell in the “Heads” layer.

After a few moments, a Heads dialog will appear, containing a plot for the selected cell.

13. Select several more cells by repeating step 12.

Selecting a number of cells creates a plot of heads over time at different locations (

Figure 9). Similarly, plots of boundary conditions using the different MODFLOW tables

(WEL, DRN, GHB, etc.) can be created.

Figure 9 Plot of simulated heads created using the Time Series Grapher



9 Conclusion

This concludes the “Working with Transient MODFLOW Models” tutorial. The following

key concepts were demonstrated and discussed:

Transient models are temporally referenced to real dates/times in the DISVars,

StressPeriods and OutputTime tables.

The Create MODFLOW Features tool is used to build map layers of transient

data.

MODFLOW layers can be quickly filtered using stress period (SPID) and K.

MODFLOW solutions can be imported using the Import MODFLOW Output tool.

Simulated heads, drawdown, and flow data are stored within the output tables of

the MODFLOW Data Model.

Use the Time filter to create views of MODFLOW outputs based on different time

options (TimeID, stress period and time step, total time, and absolute time).

The Time Series Grapher can be used to plot MODFLOW inputs/outputs at

selected cells/nodes.

Documents

ARC HYDRO GROUNDWATER TUTORIALSahgw.aquaveo.com/Transient.pdfmultidimensional groundwater data. It includes several components to represent different types of datasets, including representations